drawing a blank........

Heres my delema....i recently picked up a customer with a fairly good size lawn that takes me roughly 2 hours start to finish with my ztr. I just recieved a call from two people who also want my services in another area i do a lot of business in. What i am looking to do is loose the big lawn and pick up the smaller ones since i'm alreay in the area and its more cost effective. Keep in mind i have no binding contract with these people and would like to leave on good terms and recieve the from the previous weeks cutting. What would you say to this customer?